1. added new MaskedTextBox control
2. no longer have UpDownBase<T>
3. NumericUpDown now has new base class. Hopefully I didn't break anything, but I know I did :0)
4. By default the NumericUpDown uses doubles. To use anything else such as decimals or int you must specify the ValueType accordingly.
<extToolkit:NumericUpDown Grid.Row="1" Value="{Binding Age}" Increment="1" Minimum="18" Maximum="65" ValueType="{x:Type sys:Int32}" />